This invention relates to friction clutch driven plates and particularly, but not exclusively, to driven plates which are utilised in the friction clutches of automobiles.
A problem associated with some automobiles is that during the periods when the transmission drive is under no load, rotary oscillations occur in the gearbox producing a phenomenon known as idle-rattle.
In order to damp out the vibrations which generate idle-rattle it is known to utilise a friction clutch driven plate in which the torque load through the driven plate passes through two sets of damping springs arranged in series with each other. Very light loads applied to the driven plate are taken through soft auxiliary vibration damping springing. When the limited angular movement controlled by the auxiliary damping springing has been taken up, normal drive load passes through a set of main torsion damping springs. In this way, very soft springing is provided over a limited range of movement for very light loads and this arrangement tends to prevent idle-rattle. Such a driven plate is known from French Patent Publication No. 1501465.
It is often important for a friction clutch driven plate to be compact in order to enable it to fit within a space available in an existing design of drive line or to assist in maintaining the combination of engine, clutch and gearbox as short as possible in a completely new design.
It is also desirable in the interests of reliability and cost to provide a design which is as simple as possible.
An object of the present invention is to provide a compact and simple design for auxiliary torsion damping springing in a friction clutch driven plate.